MJ pumps may be the most versatile pump in the aquarium hobby.

Many hobbyists have grown to love these pumps over the years. In the not-too-distant past, they were referred to as "Maxi-Jet" pumps and sold by Marineland. Today they are simply called "MJ" pumps and sold by Cobalt Aquatics. Cobalt Aquatics' MJ pumps are made in the same Italian factory that has been manufacturing these awesome pumps since the very beginning.

We've found so many helpful ways to use these pumps at home and around the office that we decided to put together a list of our Top 10 favorite ways to use MJ pumps to show you just how awesome and versatile these little pumps can be!

1.) Mixing water for water changes
The excellent build quality of MJ pumps stands up to the abrasiveness of salt very well.

2.) Transfering water during water changes
The MJ 1200 pumps up to nearly 6 feet, which makes them the perfect cure for having to lift heavy buckets.

3.) Powering media reactors
The slower flow rate of the smaller MJ 400 is perfect for many GFO/carbon media reactors. The larger MJ 1200 can be used for many biopellet reactors.

4.) Feed pumps for external protein skimmers
The reliability of the pumps makes them great for these applications. Just set it and forget!

5.) DIY kalkwasser reactors/calcium reactors
Here's where the quality comes into play again. MJ pumps handle abrasiveness and particulates better than just about any other aquarium water pump.

6.) Blowing detritus out of rocks in your aquascape
The small size and focused outlet make them very easy to work with. Just point and shoot!

7.) Return pump for smaller aquariums
The small size and ability to handle pressure makes MJ pumps a great choice for smaller systems.

8.) Aerator for fish-only systems
The venturi attachment and flare outlet nozzle works extremely well to inject air into the water to aerate the aquarium. This helps to provide oxygen and raise pH in freshwater or fish-only marine systems.

9.) Water circulation inside an aquarium (and with a wavemaker!)
MJ pumps handle being turned on and off very well. Since wavemakers turn pumps on and off frequently to produce waves and randomized currents, MJ pumps work extremely well for this application.

10.) Pump for ATO systems
Nobody likes it when their ATO pump fails. MJ pumps are the perfect solution. ATO systems top off aquariums numerous times throughout the day and in very short durations. This frequent on/off and short running time is very hard on the pump. Due to the quality of the motor and the tight variance of production, MJ pumps are extremely dependable and handle this job extremely well.

Among all of the different powerheads I have used over the years, the MJ pumps have time and time again proven to be one of the best pumps for the price. They are affordable, extremely reliable and work very well for a variety of applications.

Thank you for giving us the opportunity to share our knowledge with you. If you found this information helpful, please like and share it to help us spread the word!

Don't forget to subscribe to our YouTube channel to stay up-to-date on all our latest video tutorials. Please let us know in the comments how you use your MJ pump!

Until next time, take care and happy reefkeeping.

4Shop for Cobalt Aquatics MJ Pumps in our online store.

4Shop all Submersible Powerheads in our online store.

4Watch our Pumps, Wavemakers & ATOs video playlist.